Protective device for a carburetion system



Sept. 8, 1959 FIG. 2

F. RIPPINGILLE PROTECTIVE DEVICE FOR A CARBURETION SYSTEM Filed Oct. 8, 1954 INVENTOR. FRANK RIPPINGILLE BY 7W 79m United States Patent a PRGTECTIV E DEVICE FOR A :CARBURETION SYSTEM Frank Rippingille, Niles, Mich, assignor to Clark Equip- -ment Company, a corporation of Michigan .Application October 8, .1954, Serial No. 461,074

1 Claim. (Cl. 123-120) This invention relates to protective devices for carburetionsystems of'internal-combustion engines that employ liquefied petroleum gas as fuel. Such fuel, commonly known as LPG, frequently is a mixture of butane and propane, although other components may be present.

.In an internal combustion engine that uses liquefied petroleum gas as a fuel it has been common practice to make :use cf a conventional vent type hydrostatic relief valve in the fuel flow system. A protective device to prevent excessive pressure is necessary in such a'system because abnormal conditions, such as excessive temperature, may under some circumstances increase the system pressure sufficiently to endanger the vehicle or other machinein -which theengine is located. In a conventional arrangement, when the pressure exceeds the relief valve setting, the valve opens and vents the fuel system to the atmosphere, thereby spilling liquefied petroleum gas on to the machine orelsewhere in the surrounding area. As .theliquid is very volatile and inflammable this creates ahazardous condition. 7

The principal-object of the3present inventionis to provide an improved protective device for carburetion systems of the liquefiedpetroleum-gas type that safely limits the liquid pressure Without creating any hazardous conditions.

, A :further object is to provide a simple, inexpensive, self-contained protective unit that is .durable and not susceptible to damage.

In carrying out my invention in oneform I provide a protective device comprising an enclosure connected in the fuel line between the source -.of supply of liquefied petroleum gas and the fuel regulator. This enclosure contains a collapsible device which collapses as'thepressure increases, thus increasing the volume of the liquid and restricting the pressure increase. This protects against excessive pressure but at the same time allows no fuel to escape into the surrounding area to cause a hazardous condition.

For a clearer and more complete understanding of my invention reference should be had to the accompanying drawing illustrating certain preferred embodiments of the invention.

In the drawing:

Fig. 1 is a flow diagram of a typical liquefied petroleum gas carburetion system incorporating my invention, which may be used, for example, with an engine which propels a vehicle, and

Figs. 2 and 3 are enlarged sectional views showing certain forms of the protective device in more detail.

Referring to the drawing, the numeral indicates a tank which contains liquefied petroleum gas 12. This liquid may comp-rise the source of fuel for an internal combustion engine 16 which in turn may power a vehicle (not shown). The liquefied petroleum gas is kept in the liquid state by pressure. The pressure varies with the temperature and is equal to the highest vapor pressure of one of the components of the mixture. As an example, propane develops a pressure of approximately 190#/sq.

17 and shut-off valve 18. The liquid thenpassesthroughv fuel line 20 into the protective device'22, described in detail hereinafter, which prevents -the build up of an excessive pressure inthe carburetion system.

From protectivedevice 22 .the liquid 12 passes into a filter.24 which removes-any foreign material which may be carried by the fuel. A fuel-line 26 provides a connection from filter 24 to asolenoid valve 28 locatedin the system between filteri24 andvaporizer regulator 30'. The solenoid valve 28 :is connected by an electrical conductor 34 to a vacuum switch 31 located on carburetor 32. The vacuum switch 31 receives :its electrical energy form a source, such as a battery, generally indicated by the numeral 35. To complete the electrical circuit a line 36 connects battery 35 to a fuse 38 and a conductor 37 connects the fuse to the vacuum switch 31. The vacuum switch 31 is closedtonly when there is a-vacuum in the carburetor. Therefore, whenever the engine 16 stops, switch 31 opens the circuit to solenoid valve 28.

This deenergizes and closes the solenoid valve, which cl-oses-thefuel line 26 to-the vaporizer regulator 30 and prevents any damage to the regulator due to excessive pressure.

When the liquid 12 enters :the regulator 30 it expands and vaporizes. Hot water from the engine cooling system 40 is carried to and from the regulator 30 through water lines 42 and 44. The hot water aids invaporizing the liquid and eliminates any possibility of icing conditions that might develop because of drastic pressure change.

The resulting vapor passes from'regulator 30 through a fuel line 46 to the carburetor 32. The carburetor 32 mixes the fuel vapor with .air and directs the .dry gas to the combustion chamber where it istburned completely, which is oneof-the desirable features of this type fuel system. Other advantages of this type system are: no obnoxious fumes or smoke, no dilution of crankcase lubricant, simplicity of carburetor, elimination of fuel pumpand no fuelsp-illage or .evaporationastheentire system is under sealed pressure.

.Refer'now to Fig. 2 which isa section thru protective device 22-of'Fig. l showingtheprotective device in greater detail.

An inlet 48 provides .a passageway for liquefied 'pe troleum gas into a chamber 50 provided in case 52. Located in chamber 50 is a collapsible structure or bellows 54 which consists of a circular top plate 56 of rigid material which is suitably fastened and sealed to a cylindrically disposed convoluted resilient member 58. A rigid bottom plate member 60 also is suitably fastened and sealed to resilient member 58. Plate member 60 has an outwardly extending portion 62 which projects outwardly thru a hole in case 52 and is held in place by any convenient manner such as a nut 64 as shown. Plate member is sealed to the bottom surface of casing 52 in a suitable manner. In bottom plate member 60 and extending thru projecting portion 62 is passageway 66 which connects the interior of portion 54 to the outside atmosphere. Contained within capsule 54 is a second resilient member such as a coil spring 68 which helps return first resilient portion 58 to normal expanded position. In the upper portion of casing 52 and in communication with chamber 50 is an outlet 70.

Next, I shall describe the operation of the protective device. Liquefied petroleum gas enters passageway 48 into chamber 50. If the pressure exceeds a predetermined amount, dependent upon the characteristics of resilient portions 58 and 68, the pressure causes the structure 54 to collapse, forcing the air contained within 54 out passageway 66. As the structure 54 collapses it increases the volume in chamber 50, thus decreasing the pressure here and elsewhere in the carburetion system. When the pressure decreases again, the structure 54 returns to the expanded position, as shown, under the influence of resilient members 58 and 68. 3

As the structure 54 is a sealed unit it is-impossible for fuel to be spilled or released to the outside of the carburetion system, thus eliminating the hazardous or undesirable conditions which exist with many previous pressure relief devices.

It will be understood that the auxiliary spring 68 may be omitted from the structure 54 if the characteristics of the convoluted wall 58 alone can provide the necessary resiliency in the structure.

Another embodiment of my invention is the same as illustrated in Fig. 2 except that the passage 66 connecting theinside of structure 54 with the atmosphere is omitted. In'this case, the structure 54 may float as a free unit within the chamber 50, or it still may be secured to the bottom wa ll of the casing 22 if desired. In either event, the structure 54 is collapsed by compressing the air sealed within the structure 54, thus increasing the effective volume of chamber 50 and relieving the pressure in the carburetion system in the manner previously described.

Another form of my invention is illustrated in Fig. 3 of the drawing. In this form, an annular or doughnut shaped member 72 of synthetic rubber or other suitable material is contained within casing 52. The annular member 72 is filled with air or other suitable gas the same as structure 54in Fig. 2 and collapses in the same manner as structure 54 to prevent excessive pressure in the carburetion system.

In all of the forms of my invention, excessive pressure in the carburetion system is prevented, without the necessity of Venting the system to the atmosphere and permitting the escape of some of the fuel. Thus, my protective device avoids the hazards of other protective devices. Furthermore, my protective device is simpler and less expensive to construct than many previous protective devices because no valves or other parts requiring extremely close tolerances and extremely fine manufacturing operations are present.

While I have illustrated and described herein certain embodiments of my invention which include a collapsible structure within its ovm casing or enclosure in the carburetion system, it will be readily apparent that the surrounding casing or enclosure is not essential. The collapsible structure may, if desired, be located elsewhere in the system. As an example, it could be located in the same enclosure with the filter 24.

Thus, while I have disclosed herein certain preferred embodiments of my invention, it will be understood that modifications may be made by those familiar with protec tive devices of this type. Therefore, it should be understood that I intend to cover by the appended claim all such modifications which fall within the true scope and spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

In a liquefied petroleum gas carburetion system for internal combustion engines having a source of liquefied petroleum gas under super-atmospheric pressure, a first conduit connected to said source, a second conduit adapted to be connected to an engine and a vaporizer regulator for vaporizing the liquefied petroleum gas flowing through said second conduit; a protective device connecting said first and second conduits, said conduits being maintained substantially full of liquefied petroleum gas between said source and said regulator, and said protective device comprising a housing having a chamber therein in continuous communication with said first and second conduits and a collapsible bellows defining a variable volume cavity, said bellows being continuously submerged in the liquid in said chamber, being responsive to the liquid" pressure in said chamber and being adapted to increase the volume of said chamber upon an increase in pressure of the liquid for maintaining the pressure of said liquid at or below a predetermined maximum value irrespective of variations in the temperature of the medium surrounding the source,

. and means controlling communication between said source and said regulator, said latter means having a solenoid valve located in said second conduit upstream of said regulator, a source of electrical energy connected to said solenoid valve and engine vacuum responsive switch means in said electrical connection for causing said solenoid valve to interrupt communication between said source and said regulator whenever an engine to which the switch means is adapted to be connected is in a nonoperating condition and to permit such communication whenever such an engine is in an operating condition.

References Cited in the file of this patent UNITED STATES PATENTS 651,617 Tilden June 12, 1900 1,169,250 Fulton Jan. 25, 1916 1,373,477 Angus Apr. 5, 1921 2,341,177 Cope Feb. 8, 1944 2,357,947 Gerson Sept. 12, 1944 2,544,289 Andrews Mar. 6, 1951 2,675,793 Ziege Apr. 20, 1954 2,752,758 Tann July 3, 1956 

